I really cannot see the problem in anyone knowing how you've voted, o.k. it supposed to be a secret ballot, but most people would happily give up the information to friends and family and most {if the subject arose} would telegraph thier preference by thier opinions.
I can understand people in certain countries being cautious and keeping it a secret, not wanting that knock on the door at 3 in the morning, thankfully we're not like that in this country {yet}
I don't mind anyone knowing how I vote, if the subject arises, I tell them, it's no secret. If I wanted to keep it a secret I wouldn't tell anyone, but there's people out there who already know.
They have ALWAYS known who votes for who in any election, It has NEVER been a secret ballot, being secret only refers to the general populace not knowing {i.e. the bloke stood behind you or the woman in front in the voting centre} obviously your preferences are not "broadcast" but it can be common knowledge with the people within the polling arena.
When you recieve your polling card it has your own personal number on it, this number is then is put on a master copy which is given to the staff at the polling station with your name at the side of it. The voting slip your given has it's own distinguishing marks which is married up to your number on the master sheet, this makes it a doddle to trace whoever used it and how you voted.